Process of treating fabric



Patented June 24, 193O p UNITED. STATES PATENT OFFICE ROBERT E. FULTON,F PITTSBURGH, PENNSYLVANIA, ASSIGNOIR. TO THE KOPPERS COMPANY, ACORPORATION OF DELAWARE PROCESS OF TREATING FABRIC No Drawing.Application filed June 7, 1927. Serial No. 197,236.

This invention relates to the treatment of partial solution ,orgelatinization occurs, refabric and more particularly to a process ofmoving any excess of'gelatinizing liquid and coating or filling wovenfabric with cellupressing and finishing the material in the losicmaterial. I usual manner.

An object of my invention is to provide a In order that my invention maybe clearly coated or filled fabric of improved surface set forth andunderstood, I'now describe, but quality and strength. without limitingmy invention to such spe- -A further object of my invention is to cificillustrative example, the preferred provide a process of coating orfilling fabric manner in which it is accomplished and with cellulosicmaterial that is free from performed.

certain difficulties and disadvantages of the A fabric base, which mayconsist of looseprior art. ly woven cloth, is covered with a layerof Myinvention has for further objects such pulp, such as sulphite pulp orcotton rag other operative advantages and results as pulp, or othercellulosic material in finely may hereinafter be found to obtain.divided state. The layer of cellulosic mate- The manufacture of coatedand filled fabrial may be of an. desired thickness and ric is wellknown. The processes of the may be applied to 0th sides, of the fabricprior art have, in general, attempted to probase or to only one sidethereof, as desired. duce such material by spreading a solutionSpreading the cellulosic material uponthe m of cellulosic material, suchas viscose, upon fabric base is easily accomplished in a man- 70 thefabric. The difiiculties met with in these ner Well known to thosefamiliar with the processes are not easily overcome. Viscose art. andother cellulosic solutions, such as a solu- The fabric and theSuperimposed cellution of cellulose in calcium thiocyanate solulosicpulp are more or less completely dried tion, are viscous and theviscosity of such by passing them between hot squeezing rolls solutionsissubject to variation upon exposwhereby heat and pressure is appliedure to the atmosphere, temperature fluctua thereto. 1 tions, handlingand the like. Consequently, After leavlng the rolls, the coated fabricit is very diflicult to obtain layers of celluis passed through asolution capable of :1) losic material of uniform thickness.Coneffecting partial solution or gelatinization of 0 stant care isrequired in s reading the celluthe pulp. I prefer to use a solution ofcallosic solution upon the fabric, and adjustclum thiocyanate havingaboiling point ofments of feeding devices must be made very from about134 to 140 C. and containing frequently. from 20% to% of formaldehyde,,but-

as The high viscosity of solutions of celluother calcium thiocyanatesolutions andstill s5 lose in calcium thiocyanate solutions makes othergelatinizing solutions, or solvents, it difficult to obtain thin layerstherefrom. known to the art may be employed. With Thick layers are proneto crack and peel respect to the preferred solutions, I have from thefabric base. found that beneficial. results may be ob- 40 I overcome thedifliculties and disadvantained by maintaining a temperature of tages ofthe prior art by spreading cfellulosic from 20 to 4:0 C. therein, butother tempulp upon a fabric base and subsequently peratures may beemployed, especially when Q accomplishing the partial solution orgelasolutions of different strengths or kinds are tinization of the pulpwithout, however, employed. 4% materially affecting the fabric base. Iac- The fabric is preferably not permitted to 9.3 complish this objectby coating the fabric remain in the gelatinizing bath for an eirbasewith cellulosic pulp, immersing the tended period but is removed andsqueezed Whole in a gelatinizing bath, such as a soluby being passedthrough rolls or otherwise tion of calcium thiocyanate 'of regulatedtreated to remove an excess liquid which strength, allowing the materialto stand until may have adhered t ereto. The material which now retainsa suflicient amount of gelatinizing liquid to accomplish the desiredresult is allowed to stand for a predetermined period to permitgelatinization of the pulp fibers. It may be wound upon a reel or foldedor handled in any other convenient manner during this gelatinizationperiod.

When the desired degree ,of gelatinization is attained, the material issprayed with water or subjected to the action of steam or otherwisetreated to remove or dilute the gelatinizing agent and thereby coagulatethe gelatinized material and the cloth is then passed through warmsqueezing rolls orother suitable; apparatus whereby the gelatinized pulpis pressed into, and incorporated with, the fabric base. and dried inthe usual manner.

According to the results desired, the raw materials of my process andthe procedure thereof may. be varied over a wide range, as will beapparent to those skilled in the art. For example, fabric bases wovenfrom flax, hemp, jute, or other fiber may be treated and the cellulosicpulp employed 'as fill-- ing or coating agent may be obtained from manysources.

Moreover, the sequence of steps may be varied in carrying out theprocess of my invention. For example, under certain circumstances, itmay be advisable to squeeze or press the coated fabric before sprayingor steaming it to dilute the gelatinizing agent.

The natur'e of the product obtained in the process of my invention willvar :ac-

, cording to the materials employed an also according to various otherfactors, such as the duration of the period of gelatinization.Ordinarily, however, I prefer to allow gelatinization of the pulp toproceed to the greatest practicable extent without, however, materiallyaffecting the fabric base. Partial gelatinization of the fabric base,however, is not necessarily a disadvantage as it may assist in forming abond between the base and the coating material.

The advantages of my process are at once apparent to those skilled inthe art. The

difliculties of handling extremely-viscous cellulosic materials that maybe subject to fluctuations in viscosity are entirely obviated. Thecoating or filling which results The cloth is then washed fabric andsubjecting the fabric and pulp to a liquid effective to gelatinize thepulp.-

3, The process of treating fabric which comprises spreading cellulosicpulp over the fabric, subjecting the fabric and pulp to the action of acellulose solvent, allowing gelatinization of the pulp to take place andremoving excess solvent.

4. The process of treating fabric which comprises spreading cellulosicpulp over the fabric, immersing the fabric and pulp in a solution of-calcium thiocyanate, removing the fabric and pulp and allowing them tostand until the pulp is at least partially gelatinized but withoutmaterially affecting the fabric and pressing the gelatinized pulp intothe fabric.

5. The process of treating fabric which comprises spreading cellulosicpulp over the fabric, pressing and drying the fabric and pulp, immersingthe dry material in a solution of calcium thiocyanate' and formaldehyde,removing the treated fabric and pressing it to remove excess solution,allowing it to' stand until gelatinization of the pulp occurs, removingthe remaining solution and washing and drying the coated fabric.

.6. The process of treating fabric which comprises spreading finelydivided cellulose over the fabric, subjecting the whole to the action ofa cellulose solvent until gelatinization of the applied cellulose iseffected and subscribed-my name this 2nd day of J une,

ROBERT R. FULTON.

is much more uniform and adherent and will not crack or peel. Moreover,a considerable saving 1n chemlcals is-effected.

My rocess is not limited to the specific I examp es given hereinabove byway of i us- I claim-as my invention: Y 1. The process of'treatingfabric which comprises spreadingcellulosic pulp over the tration' but mavariously be embodied within the scope o the claims hereinafter made.

fabric and then effecting a gelatinization of i the pulp.

